This is an application for funding of a Population Research Center at Princeton University in the Office of Population Research (OPR). The Center consists of an Administrative Core, a Data Analysis Core, and a Library Core, which provide services to individual investigators working on demographic research within the Center. There are currently 24 professional researchers associated with OPR working on projects in several major areas of demographic research. During the first two years of the proposed Center grant period (beginning on July l, 1994), on-going research will include investigations of: the performance of methods for indirectly detecting fertility control; the early-age precursors of older-age morbidity and mortality; marital status, health, and mortality among the aged; ways to reduce the risk of sexually transmitted HIV infection in black junior high school students; infectious disease, immunization, and host dynamics; demographic dynamics of childhood disease and mortality; family change, family resources and child well- being; child support reform and child well-being; the interrelations among saving, aging and inequality; health care choices during pregnancy and child illness in Guatemala; and impacts of immigration in New Jersey.